The Three Protocols Powering Agentic Commerce
UCP, ACP, and AP2 are the three open standards that govern how AI agents discover, transact with, and cryptographically trust businesses. Together they form the complete agentic commerce infrastructure layer. Businesses that implement all three are visible, transactable, and trusted by AI agents — those that don't are invisible to the fastest-growing commerce channel in history.
UCP vs ACP vs AP2
Each protocol operates at a distinct layer of the agentic commerce stack.
Explore Each Protocol
Deep-dive into the specification, implementation details, and code examples for each protocol.
Universal Commerce Protocol
The AI agent discovery standard. A JSON manifest at /.well-known/ucp/manifest.json tells every AI shopping agent what your business sells, how to transact, and which transport protocols you support.
Agentic Commerce Protocol
The AI checkout execution standard. ACP defines how AI agents ingest product feeds, initiate purchases via Stripe Payment Tokens, and confirm orders — powering ChatGPT Instant Checkout.
Explore the Protocol Manifests
See the actual JSON served to AI agents at each /.well-known endpoint — and how each protocol works in practice.
Universal Commerce Protocol
AI Agent Discovery Standard
UCP enables AI agents to discover your business capabilities, products, and services through standardized manifest files. Published at /.well-known/ucp, a UCP manifest tells every AI shopping agent exactly what you sell and how to transact.
Key Use Cases
- Google AI Mode product discovery
- Perplexity Shopping
- AI agent capability queries
- Merchant onboarding automation
{
"ucp_version": "2026-01",
"organization": {
"name": "Adam Silva Consulting",
"url": "https://www.adamsilvaconsulting.com"
},
"capabilities": [
{
"type": "service",
"id": "aeo-audit",
"name": "AEO Audit",
"price": { "amount": "500", "currency": "USD" }
}
],
"transports": ["REST", "MCP", "A2A"]
}Live manifest served at /.well-known/ucp/manifest.json — AI agents discover this automatically.
Protocol Questions Answered
What is the difference between UCP, ACP, and AP2?+
UCP (Universal Commerce Protocol) handles AI agent discovery — it publishes what your business sells and how agents can interact. ACP (Agentic Commerce Protocol) handles checkout execution — it defines how AI agents initiate and complete purchases. AP2 (Agent Payments Protocol) provides the cryptographic trust layer — it issues Verifiable Credentials that give agents legal authority to transact on behalf of users. Together they form the complete agentic commerce stack.
Do I need all three protocols, or can I implement them individually?+
Each protocol serves a distinct layer, but they work best together. UCP alone makes you discoverable but not transactable. ACP alone enables checkout but agents may not discover you. AP2 alone provides trust infrastructure but nothing to transact. A complete implementation — UCP for discovery, ACP for execution, AP2 for trust — is required for full agentic commerce readiness.
Who governs UCP, ACP, and AP2?+
UCP and AP2 are governed by Google as open standards. ACP is led by OpenAI in partnership with Stripe. All three are designed to be interoperable and vendor-agnostic, though each integrates deeply with its governing organization's AI commerce infrastructure.
How long does it take to implement the full UCP/ACP/AP2 stack?+
Adam Silva Consulting's full protocol stack implementation takes 16 weeks. Weeks 1-2 cover AI readiness auditing. Weeks 3-6 deploy the foundation layer including UCP manifest, AP2 infrastructure, and JSON-LD schema. Weeks 7-10 implement ACP checkout with Stripe SPT. Weeks 11-16 add the authority layer and final verification. Enterprises with existing APIs and modern tech stacks can often move faster.
Ready to Implement the Complete Stack?
Adam Silva Consulting implements the complete UCP/ACP/AP2 stack — from the initial ACRA through full protocol deployment. 16 weeks to agentic readiness.